Vitreoretinal surgeries typically include continuous irrigation to, and continuous aspiration from, a surgical site undergoing treatment. Aspiration typically includes a vacuum used to remove fluid, tissue, and debris from the surgical site. However, care should be taken during aspiration to ensure that, along with the fluid, only debris and unattached tissue are drawn into the aspiration path. Without such care, tissue can become inadvertently incarcerated into the aspiration path. Incarceration of tissue into the aspiration path may cause additional surgical setbacks to be overcome during the surgery. For example, when fluid is removed from a subretinal space in retinal detachment treatments, the retina may become vacuumed in the port of the aspiration tip. This can, for example, lead to enlargement of the retinal tear or tissue damage. Retinal incarceration can also occur when users place an aspiration tip of the instrument underneath a detached retina to remove subretinal fluid. Since the visibility through the detached retina is limited, the user risks incarcerating tissue since he or she may not see the instrument tip clearly. It can also occur when the operator aspirates subretinal fluid close to a retinal break. Due to the fluid turbulences, the detached retina moves and can become incarcerated as well.
Some conventional treatment instruments permit a user to disrupt aspiration depending on hand or finger placement over a hole in the aspiration line. However, if the user does not react quickly enough in case of incarceration, tissue damage can occur. Further, if the user makes an unintended motion when tissue is incarcerated, it too can lead to retinal holes or to an enlargement of the retinal tear.